Tonal variations on human skin have multiple causes. Acne, freckles, sun damage, and age spots are just a few of the common causes of visible defects on skin. Textural variations such as fine lines, wrinkles and scars are also well known. Both tonal and textural deviations are noticeable to the human eye, even when they are quite small. Covering large areas of skin on and around deviations with makeup or other concealers is known.
Moreover, attempts have been made at more precise, and localized application of compositions that hide, or cover-up skin deviations. Handheld devices that are moved across the skin have been developed to apply skin treatment compositions to local defects. But these devices have been plagued by the absence of two necessary components, speed and accuracy. For these handheld devices to work effectively, they must find the defects quickly, and treat them immediately. Finding a spot on the skin is of little use if the user has moved the applicator head to a different area of the skin before the spot can be effectively treated.
Therefore, there exists a need for methods and apparatuses that can quickly and precisely detect tonal and textural defects on skin. Then with equal speed and precision, apply treatment compositions directly to the deviations. These methods and apparatuses are defined by the present specification.